252 Proceedings of the Royal Physical Society. 



ably not far removed from the sandstone which yielded the 

 other two series. 



The specimens brought home by Mr Bruce, as well as 

 those previously recorded from the Falkland Islands, are so 

 similar to the Brachiopods obtained from the Bokkeveld 

 beds of South Africa, that there can be little doubt as to 

 their being from beds of approximately the same age; and 

 Mr Reed's statement that the Bokkeveld fossils exhibit a 

 Devonian facies is therefore strong confirmation of the 

 opinion expressed by the earlier writers as to the Devonian 

 age of these Falkland Island fossils. 



1. S'pirifera antarctica, M. and S. (PL X. Figs. 1-10). 



By far the greater number of the fossils brought home by 

 Mr Bruce are referable to the genus Spirifera, and most of 

 them, as I think, to the species S. antarctica. At first sight 

 there seems to be a considerable difference in the forms, some 

 of the valves being much coarser than others; but when 

 examined more closely it will be found that the dorsal valves 

 have eight or nine ribs on each side of the median fold, and 

 the ventral valves nine or ten ribs on each side. The width 

 of the ribs varies somewhat in different specimens, and the 

 lines of growth are sometimes very strongly marked and 

 irregular; besides this, the ventral or grooved valves have 

 the ribs more or less angular, while in the dorsal or ridged 

 valve the ribs are more rounded. The hinge-area is wide, 

 concave, and marked by distinct longitudinal lines. The 

 deltidial opening seems to have occupied about half the 

 height of the area, which is marked on each side of the open- 

 ing by a distinct groove forming an inverted A (Fig. 5). 



Among these Spirifers I do not find so much variation in 

 the number of the ribs as is figured and described by Morris 

 and Sharpe. The largest specimen (Fig. 3) is a ventral valve, 

 it is about 80 mm. wide and about 35 mm. high ; while the 

 smallest specimen, which seems to belong to the same species, 

 is a dorsal valve, 16 mm. wide and 10 mm. high. The best 

 preserved example (Fig. 10) is a dorsal valve, 53 mm. wide 

 and 19 mm. high ; the greatest width of the convex median 



